Chlorine dioxide (ClO2) is an agent that is used annually in the U.S. at a rate of approximately 4 million pounds per year, primarily for water purification and wood pulp bleaching as a replacement for chlorine/hypochlorite. Chlorine dioxide is an effective microbicide as a gas and in solution and also can destroy certain chemical substances and toxins. Chlorine dioxide has excellent environmental qualities, as it does not produce large quantities of chlorinated hydrocarbon byproducts. Many processes are known for the production of ClO2 in gas or solution forms suitable for large-scale use. Typically, rather cumbersome equipment is needed to produce ClO2 solutions, such as, electrolysis cells and DC power supplies for ClO2 generation. Generally, the ClO2 solution has a very finite lifetime and must be used approximately within the day it has been generated.
Chlorine dioxide solutions can be produced by treatment of chlorite salt solutions (e.g., NaClO2) with a strong acid to produce acidic solutions that contain ClO2. Ion exchange media can be used for the formation of chlorine dioxide; for example, Callerame, U.S. Pat. No. 3,684,437 discloses production of chlorine dioxide by ion exchange between a mixed bead cation-anion exchange resin and a chlorite of an alkali metal or an alkaline earth metal with a very slow flow rate. Similarly, U.S. Pat. Nos. 7,087,208 and 7,824,556, both to Sampson et al disclose generation of chlorous acid from a chlorite salt precursor by passing an aqueous solution of the precursor through a cationic ion exchange resin in a hydrogen ion (acid) form and a catalytic material to accelerate the decomposition of chlorous acid to chlorine dioxide using gravity feed at a moderate rate.
A method for ClO2 production, which can be conveniently and safely performed using a redox-modified resin in conjunction with a chlorite precursor solution or absorbed chlorite and water that can be combined in a portable device, is disclosed in Richardson et al., U.S. Pat. Nos. 7,964,138 and 8,323,563 and Richardson, International Patent Application Publication Nos. PCT/US2013/054724, and PCT/US2014/020178. The devices disclosed therein are designed such that the reactive components are contained in separate containers until solution generation is desired. These methods require the feeding of liquid through one or more reactive beds to produce ClO2 solutions. Although the method of Richardson et al. is useful for commercial and even portable emergency production of chlorine dioxide, the containment and storage of a relatively large amount of an isolated aqueous solution as the feed solution is required. Therefore, a method of retaining both complementary reagents in a bound state, such that any available water can be used as the liquid feed, rather than a specific precursor-containing solution, is desirable for reduction of the complexity and size of a chlorine dioxide generator.
Schroeter et al. U.S. Patent Application Publication No. 2013/0089473 teaches a device to facilitate the generation of ClO2 where a chamber of NaClO2 and a chamber of a solid dry acid are formed about a dissolvable barrier separating the two chambers. The device can be submerged in water in a container designed to hold a sufficient quantity to swell the contents of the chambers, which ultimately dissolve the barrier and mix the ClO2 precursors to generate ClO2 gas that diffuses from the device to introduce ClO2 gas to a space to be disinfected or deodorized.
Andrews et al. U.S. Patent Application Publication No. 2013/0017241 teaches a ClO2 generator that is in the form of a tablet or capsule where a core portion contains a solid acid and a metal chlorite dispersed in a porous solid vehicle and is covered with at least one protective layer that is water permeable, particularly a polyalkyleneoxide polyvinyl alcohol copolymer, over at least a portion of the core. The generator is placed in water to dissolve and mix the reactants, which liberates the ClO2 from the core into solution or as a gas.
It is desirable to have a ClO2 impregnated wipe for use for viral or bacterial disinfection or cleaning of contaminated surfaces. It is also desirable that the wipe can be activated with water and rather quickly generates ClO2 solution for use on demand in a controlled manner at ambient room temperature.